Dielectric and magnetic response of Sr–Zn ferrite composite

Abstract

Sr–Zn ferrite composites were synthesized by chemical coprecipitation with different sintering process. The composites were characterized by XRD, XPS, IR, VSM, and N₂-adsorption. The results revealed that the composites were composed of S-type ZnFe₂O₄ and M-type SrFe₁₂O₁₉. Zn²⁺ ions inserted and occupied the 12k or 2a sites for Fe³⁺ ions in M-type SrFe₁₂O₁₉. The Zn²⁺ ions were therefore not on the external surface of the composites. The microwave absorption properties at a frequency range of 0–18 GHz were estimated using the electromagnetic parameters obtained through the agency of microwave vector network analyzer. The microwave absorbing properties of composites were excellently superior to that of the pure SrFe₁₂O₁₉ or ZnFe₂O₄ due mainly to the exchange coupling between the hard- and soft-magnetic phases. The synthesis process was found to facilitate mass production for various composite materials, especially the two phases or multiphase composite materials.